Method of and apparatus for making dry-cell cores



Nov. 18, 1930., J; M. HENDERSON 1,781,688

' METHOD OF AND APPARATUS FOR MAKING DRY CELL coims 4 Sheets-Sheet 1 Filed Dec. 21, 1927 INVENTOR J5Jep/I Mflendmson ATTORNEYS Nov- 18, 1930. J. M. HENDERSON 1,781,53 METHOD pr AND APPARATUS FOR MAKING DRY 021.1. Conss Filed Dec. 21, 1927 4lsu ets-sueet 2 INVENTOR fife M llama/v00 BY Pam o/l'd Wa l VIM Y ud.

. ATTORNEYS Nov. 18, 1930. J D RS 1,781,688

METHOD OF AND APPARATUS FOR MAKING DRY CELL CORES Filed Dec. 21,- 1927 4 Sheets-Sheet 5 INVENTOR Jo e M flan/anion Nov. 18, 1930./ J. M. HENDERSON 7 1,731,688

METHOD OF AND APPARATUS FOR MAKI II NG DRY CELL CORES Filed Dec. 21, 1927 4 sneets sneet 4 INVENTORY Josey/7 M flawdemon WW 6 M ATTORNIFYS 7 BY I W, Mann/1M Patented Nov. 18, 1930 n man. nnlvnnnsoiv; or mAnrsom-wisconsnv, ssrG v'oRf 'ro :BUnGnssiaAr'rEnY i COMPALNY, OFSMADISTOVIQIWAISLCQNSIN, A'conrormrron or .wrscoivsm Y METHODIOFY ANnArrAnA'rUs ronMAjKINGjnRY-"oErL corms Application filed December 21, 1927. Serial No. 241,585.

.This invention relates to-an: improved method of tamping depolarizing cores for dry'cells. i "It is anobj ect of this invention to provide 7 ua-method for automatically preventingthe depolarizing mix from adhering to the face of the tamping carbon rod atthe top'ofthe core and thereby decreasethe contact resistance. A still further object is to permit the economical pro- I duction of coreshaving convex'tops andto bag-type dry cell is'usually molded before. introducing it into the zinc can. The core.

is made ofa moistmixture of depolarizer,

ite, sal ammoniac, zinc chloride and'water in sufficient amount to allow the core to be molded readily. A carbon rod having a brass cap may bemolded into the core during the molding operation. However, my invention relates to a core made by molding the de polarizin'g'mixture and then inserting the carbon rod as described in Hambuechen Patent No. 1,282,297. The moist depolarizing compressed to form a coherent cylindrical core. The carbon rod isthen inserted into the'core after which the core is ejected from o the mold. These operations may be carried out on a tamping machine as described in tool'or knock-out punch dur-- ing themanufacture of the core. .It is a further object to produce; a core .havingex- 10": cellent adherence between the mix *andflthe provide a core. having a top whichis freeof loose particles of depolarizing mix. Further usually manganese dioxide, pulverized'graphmix is placed ina suitable mold where it is Patent No. 1,232,297 (51 they may be carried out r .on automatic machines that are power driven.

A core made as described-is often defec tive.v If thecarbonrod is driven into a cylindrical core at ;a slight angle to its own aXis, a hole is formed at the top of the core which is larger in diameter than-the rod. As aresultit-here is poor contact and a: highcontact resistance between the depolarizing mix and the rod. Thisis detrimental to the finished dry cell because the high contactresistance increases the internal resistance, lowers thershort circuit amperage or-- flash,

and decreases its electrical output. The sur- 4 face of the tamping tool contacting with the mix picks up the wet mix and soon becomes rough; The top surface of the core vthen becomes..uneven and loose particles of mix adhere to it. These loose particles of mix are a source of. potential injury to a dry cell; because if they iall into ,the zinc. can and contact therewith 'destructive'local action results. This difliculty is accentuatedv by. the v V tendency of the carbon rod to loosen the mix slightlyat thetop of the core. My invention overcomes these difficulties and is especially suitable for application to power driven core machines as distinguished from the hand op erated machines. However, I do not restrict my inventionto such machines as, it may be used in hand operated machines as well; Inillustrating the invention, I have shown a--wellknown type of pressstructure com- 1 prising a base.1,,and side walls2 at the rear of the base; The walls a 2 provide bearings fora crank shaft3 which may be driven by any. suitable means (not shown). The

cranks 4 areconnected to the shaftto cause reciprocation of'a connecting rod 5. ,The connecting rod is adapted to drive a gate 6 moving up and down in vertical guides provided in the side walls. I

A hopper, 7 fjis adapted to contain the' de-.; polarizing mix which is conveyed tothe of-thepressin any suitable manner.. The

dies:

parts exposed to the depolarizing mixture 7 are made: of, or covered with, non-corrodible material. 'A seriesfojf cylindrical dies Sare setjjin a dial 9. arranged .onthe base of themachine so that the dies pass consecutively under the feed opening of the hopper 7 to receive charges of the depolarizing mix. The

dies and the face of the dial are covered or mixis being pressed therein. A portion of the plate maybe cut away, to permit imper-' fectly formed cores to dropout of the and con'ipleted -cores to be ejected. r

The dial may be given a step by step, ro-

dies

Y tating movement by suitable means (not shown) such as the well known Geneva mo tion. After the depolarizing mix has been placed in'the die, it is subjected to three operations, namely, tamping, v inserting the carbon pencil and ejecting the-finished electrodes. In F ig. 2 of the drawings the parts of the machine are shown arranged in longitudinal alignment and after a diehas been 'filled with the requisite quantity of the depolarizing mix from the hopper T, as indicated at A, it passesto the second position and is tamped, as indicated at B. The die then passesto the third position'where the carbon pencil is inserted, asindicated at C, and eventually reaches the fourth position where thecompleted core is ejected from the die by the knock-out punch, as indicated at D.

'A tamping; toolis carried'byi the gate 6 andis adapted to be reciprocated into each of the'dies at the second position B while the dialis in a state of restto properly tamp the depolarizing mixturep As shown (see Fig. 2) the tamping tool is provided witha conical lower face 12. The tamping tool is provided with a pin 13 which works in a socket in a head 14. Thissocket is threaded and is fastened by means of a nut 15 and a stud 16 in the gate of the press. An arm 17 extends through a slot in the socket 14 to permit the tamping tool to be twisted in the socket. This arm is in turn attached to an arm 18 to synchronize the twisting of the tamping tool with its reciprocating movement. Any suitable moving part of the'machine may beemployed to twist the tamping tool. On the downward stroke of the tamping tool the mix is compressed in the die against the bottom plate 10 to form a firm, hard, cylindrical slug of uniform densityin the lower part of the mold. 'The pressure em loyed firmlywedges the core into the mold but the mix has a tendency to stick to the bottom face of the tamping tool with i i which itcontacts, if the toolis not twisted at the proper time. Heretofore some tamping tools have been provided with fiat faces from which the adhering mix may be read ily removed by a scraper, but with a conically countersunk face this accumulated mix is diflicultto remove from the face of the the surface of the tamping tool remains clean and no timeis lost in cleaning the tool. This is true where the tool is-provided with a 7 straight or countersunk face. The surface of the core 'is'sm'oo'th andf'ree of loose par ticles. To obtain this twisting movement the arm 18 is connected to a pivoted lever 19 which is pivotallymounted at 20 onthe gate 6 of themaohine and-is provided with an engaging portion 21 at its upper end adapted tocontact with aneccentric 22 on the drive shaft. The upper end of this lever is normally urgedinwardly by. 'a spring 23 connectedto'a stationary part of the machine and to an arm or bracket 24 carried by the. lever. The-lower end of this lever is pro.

vided with an opening to, receivethe arm 18 and is. retained thereon by nuts 25. A spring 26 may surround the arm 18 to keep the lower end of the-lever 19 normally in its outer position. When, the arm.'19 is rocked on its pivot the arm 18 is swungthrough an arc of a circle causing the tampingtool to be twisted in the head or socket .14.

After the mix has been tamped as described, the dial 9 is rotated to position the compressedcore under the carbon inserting mechanism. Thecarbon rod is then pushed into the mix as shown in F 2. of the draw ings. The carbon inserting means consists of a plunger 27 operating in a head 28 to force the carbon pencil through the tamped mix cake. As the carbon inserting mechanism forms no part of the present invention a detailed description thereof is deemed unnecessary. After the carbon has been inserted the dial moves to the position Dunder the knock-out punch 29 whence the completed core is ejected. The knock-out punch is recessed, as at 30, to accommodate the projecting head31 of the carbon pencil. Thecore is removed from thedie by pushing on the de polarizing mix and not onthe carbon. The

punch'maybe provided with a fiat face or may be countersunk as indicated at 31. In Figs. 2 and 3' of the drawings, the punch is shown at the bottom of its stroke. Since the mix cake is wedge-d tightly in the die by the tamping tool considerable pressure is necessary to push the core through the mold. The starting pressure is especially high. As a result, the face of the knock-out punch becomes cov ered with mix-causingdifficulties similar to those experienced with the tamping tool as heretofore described. I have found that these difliculties may also be avoided by twisting the knock-out punch on its deknock-out punch as described makes it possi-' ble to use'these tools with countersunkheads;

' V thanin others. i The twisting movement evens off the; top "and causes an adjustment .of

-scent throughgthe'sdie, especially while it is r inwc ontactiwiiththe top of thecore. The

punch need not be twisted after the core has been ejected frQm thebottom ofithe mold. The'punch 29 ismountedin a head 32which is in turn carried by the gate 6:. An armor pin- 33' is carrie d by the punch which; passes in a slot" 37 formed in a plate-38 carried by a stationary part of the machine so that during.v

the downward movement of thegate the arm 34 i's'swung on its pivot. The lower end of the; lever 34:- is provided with an opening to re-. I ceive the arm 33 and'the arm is surrounded, by a spring 39 which engages oneiside'of the -lever.' lWhen-the' lever-34 isfswung on its pivot, the arm 33=m0ves through an arc of a circle to twist the knock-out punch.

being earried by the gate of the press are syn- 3 chronized in their movement and the twisting of each' of these tools, being controlledfrom .a.

at the desiredtime with respect to that tool.

The twisting of the tamping tool and the The countersinking maybe conicalin shape.

As pointed out the twisting of the tools cleans the surfaces of the toolscontacting with the mix and obviates the-necessity of shutdowns to clean the tools. Inv addition the convex top of the finished core adds depolarlzlng mm at a place on the corewhich'adds to the. dis. charge capacity without interfering with the:

expansion of the'pasteelectrolyte' used in the pasted type of dry cell well known tothose skilled in the art. When the carbon is inserted into the core the mix may be disturbed and loosened adjacent tothe carbon at the top of the'core. The carbon'also'may be in poor contact with the mix as hereinbefore explained. I have discovered that the difficulthan the cone in thetamping tool the entire pressure of the knock-out toolis concentrated on the mix adjacent to the-carbon. As a high pressure is necessary to'eject the core from the mold, the deterimental effect on the mix caused by the insertion of the carbon is corrected. The mix is recompressed and m addition it is forced against the carbon. so that itadheres tightly tothe carbon especially at the upper part of the core. I The contact resistance is thereby cut to a minimum. I have found that excellent results are obtained if the The tamping tool 11 and the knock-out punch 29,

face, of lthe counter-sinking of the z'tampin'g tool is atan angle ofabout.3O9 with a plane perpendicular to the axis of the tool and if vthe angle of the countersinking of the knock-t9 out punch isnabout 209. .WhileI have described a countersunkconehaving anglesof g 1 approximately3Q and 20? Ido not wish tolimit myself .tova cone of these. anglesythese I" beingmerelyillustrative of my. invention;

do. not wish mconfine toconcave or comically countersunktools-Ethe lessening ofthe angle of the knock-outpunch as compared to .the' tamping toolso as to concentrate the pressure:

of theknockbut tool to the mix adjacentto the 'carbonrod, as thisinvention maybe applied to toolsQwhich are flat orslightly con vex. I

- Thetwisting ofth e tampingtool during the act-of compressing the mixiintoasslug i creates anadvantage in. addition to those mentioned above. r If :thetool istwisted dur ing the period of compression and especially durinmthe period of heavy compressiom-a hopper greater isv the tendency toward anuneven deposit of-mix. -A tamping tool whichdoes not :rotate or twist as it: d-escends-wwill' com-r press the mix asiit is found and theresulting slug will be more compact in some places particles in the body v.of-the mix to securean even pressure at. all points. It isthus seen that the twisting of the. tamping tool pro-.

ducesa slugliavingfuniform density throughout itsmass. .Likewise, the twisting'move' mentof the vknock-out punch'tends to distribute evenly the pressure throughout the hnishedacoreand results in acoreyof more uniform density. i

Iclaim: x 1 j 1. Means for makinga cylindrical dry cell core-comprising an opentopcylindrical mold with a removable =b ottom,-t a tamping tool;

having a conically'countersunk face with the face'of said cone at an angle of about 30 with a plane perpendicularto the axis of the tool, means for reciprocating said'tampingtoo]. in said mold to compress moist"depolarizing mix previously introduced intosaid mold, means fortivistingcsaid tamping stroke and. first part of its upward-stroke," means for ejecting saidicore from said-mold, said means comprising. a cylindrical knock-x out punch having a comically countersunk tool during the last part of its downward face with the face of saidcone at an angle of abo-ut20-withaplane perpendicular to the axis of said-punch and having a recess to accommodatea carbon rod pro ecting up-j ward from saidfmix, meansfor' reciprocating said punch to push through and-discharge said corefrom the bottom of said mold, and means for twisting said punch during its downward stroke while contacting with said 2. Means. for i naking cylindrical dry cellcorecomprisin'gan open top cylindrical mold with airemovable bottom, a tampingtoolhav lnga coni'callycountersunk face, means for reciprocating said tamping toolin'said mold to'compress moist depolarizing rmix pre-' viouslyintroduced into said mold, means for twistingusaidtamping tool during'the last partcof its-downward stroke and first part of its upward stroke, means for ejecting said core from said mold, said meanscomprising a-c lindrical knock-out punch having a conical y countersunk face, the face of said cone bei'ngat an angle with a plane perpendicular to theaxis of said punch less than the angle of the cone in said tamping tool, said knockout punch'havi'ng-a recess to accommodate a carbon rod projecting upwardfrom saidmix, means for reciprocating said punch'topush through and discharge said core from the bottom of said mold, and means for twisting saidpunch during its downward stroke while contactingwith said mix; r

,3. 'Means. for making a cylindrical dry cell core comprising an open top cylindrical mold 1 with a removable bottom, a tamping tool having aconically countersunk face,lmeans for reciprocating said tamping tool in said mold to compress moist'depolarizing mix previously introducedintosaid mold, means for through and discharge said core from the bottom of said mold, and means for twisting said punch during its downward stroke while contacting with said mix.

4. Means formaking a cylindrical dry j cell core comprising an open top cylindrical mold with a removable bottom, means for reciprocating a tamping tool in said mold to compress moist depolarizing mix previ ously introduced into said mold, meansfor twisting said tamping tool during the moment of relieving the pressure of said tampingtool on said mix, means for ejecting said core from said mold s aidmeans comprising a cylindrical knock-out punch having a recess to accommodate a carbon rod, projecting upward from said mix, means for reciprocating said punch to push through and discharge said corefrom the bottom of said menses"- mold ,'andrmeans for. twisting said punch during .its downward stroke while contactingwithsaid mix. i 7

=In means for making a cylindrical dry cell'core,l-a tampingtool having a countersunk face, means for reciprocating said tamping tool, meanstfor twisting said tamping toolduring'the last part of its down ward stroke and first part of its upward stroke; a cylindrical knock-out punch having a'face countersunk more shallow than the faceoffsaid tampingtool, means for reciprocating said punch, and meansfor twisting said punch during its downward stroke. Y

6. In means for making a cylindrical dry cell core, a tamping tool and means for reciprocating said too1,:means for twisting said tamping tool duringthe'last part of its downward stroke-and first part of its upward stroke, a cylindrical knock-out punch, means for reciprocating saidpunch, and

means for twisting. said punch during its downward stroke.

7. In means for makinga cylindrical dry cell'co're," a tamping tool having a countersunk face, :means i for reciprocating said tamping'tool and means for twisting said tamping tool during the last part of its downward stroke and first part of its upward'stroke. I

'8.- In means. for making a cylindrical dry cell core, a tamping tool andvmeans for reciprocating saidtamping tool, and means for twisting said tamping tool during the last part of its. downward stroke and first part of its upward stroke,

9. Inmeans for making a cylindrical dry cell core, an open top cylindrical mold, a tamping tool, means for reciprocating said tamping tool'in-said mold to compress moist depolarizingmix therein, and means for twisting said tamping tool during the moment of relieving the pressure of said tamping tool on said mix.

10. In 'means for making a cylindrical dry cell core, a tamping tool and means for twisting the tamping tool during the moment of relieving the pressure of said tamping tool on said mix.

11. Ina'nejecting mechanism for dry cell cores aknock-out punch having means for concentrating the pressure upon the mix of the coreadjacent the carbon rod therein.

.12; In means for making a cylindrical dry cell core, a tamping tool having a countersunk face and a knockout punch having a countersunk face more shallow than the countersunk face of the tamping tool.

13. In means for making a cylindricaldry cellcore, a knock-out punch having a countersunk ejecting surface and means for twisting said punch while contactingwith said core.

14. ,Thevmethod of makinga cylindrical dry cell vcore which comprises compressing ymoist depolarizing mix to form a cylinder having a conical top, inserting a carbon rod into said cylinder, and recompressing the top of said core about the carbonrod with 5 a force having a component inwardly directed toward said carbon rod. '15. The method of making a cylindrical dry cell core which comprises inserting a carbon rod into a cylinder of compressed 1o depolarizing mix, and then recompressing the top of said core about the carbon rod with a force having a component inwardly directed toward said carbon rod.

16. The step in the method of making a cylindrical dry cell core of moist depolarizing mix which comprises twisting the tamp- 7 ing tool at the moment of relieving the pressure of said tamping tool on said mix.

17. The step in the method of making a cylindrical dry cell core of moist depolarizing mix which comprises twisting the tamping tool during the period of heavy compression between said tamping tool and said mix.

I 25 In testimony whereof I aflix my signature.

JOSEPH M. HENDERSON. 

